JP4708623B2 - Fuel cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell used for, for example, an automobile, an emergency power supply, or a distributed power supply.
[0002]
[Prior art]
Fuel cells have been attracting attention in recent years because they have a low environmental impact during operation, and they are used as distributed power sources and automobile energy sources because they emit little harmful exhaust gas and can be installed in urban areas.
[0003]
One important point is how to increase power generation efficiency for the spread of fuel cells. For this reason, various improvements such as improvements of electrodes and separators have been made. In addition, it is generally known that when the supply air is humidified to increase the efficiency of the fuel cell, the power generation effect is improved. For example, Japanese Patent Laid-Open No. 6-132038 shows that a water vapor permeable membrane is used to humidify supply air and fuel, and moisture is exchanged between exhaust and supply air.
[0004]
Those using such a water vapor permeable membrane require a water vapor permeable membrane having a large area, and it is difficult to reduce the size of the fuel cell. For this purpose, there has been developed a method in which water is heated to generate water vapor and the supply air is humidified with the water vapor.
[0005]
[Problems to be solved by the invention]
However, when a humidifier is provided, there is a problem that the energy consumed by the humidifier itself is large, and as a result, the efficiency improvement result cannot be obtained.
[0006]
The present invention seeks to provide a fuel cell that is small in size and has improved efficiency by humidifying the air sent to the fuel cell with the discharged steam. Furthermore, it is an object of the present invention to provide a fuel cell that can supply a sufficient amount of steam even when the fuel cell is activated, and can increase the efficiency at the time of activation and speed up the activation.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention solves the latent heat as well as the sensible heat between the air intake pipe and the air exhaust pipe and between the fuel intake pipe and the fuel exhaust pipe from the battery cell. Has a rotary moisture / heat exchanger that replaces the air, and a heater that heats the air and fuel before passing it through the humidification passage of the rotary moisture / heat exchanger is installed. The rotation of the heat exchanger was made slower than during normal operation.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, latent heat is generated along with sensible heat between the air intake pipe and the air exhaust pipe and between the fuel intake pipe and the fuel exhaust pipe from the battery cell. It has a rotary humidity / heat exchanger to be exchanged, and the air or fuel is sent to the air or fuel intake pipe through the humidification passage of the rotary humidity / heat exchanger, and the exhaust is rotary humidity / heat exchange. A heater that heats the atmosphere or fuel before passing it through the humidifying passage of the rotary humidity / heat exchanger is provided to operate the heater at the start of operation and the rotary humidity.・ Rotation of the heat exchanger is slower than in normal operation. At the start of operation, moisture remaining in the humidification passage of the rotary moisture / heat exchanger is taken in and supplied to the air or fuel. Moisture It has the effect of supplying.
[0009]
【Example】
Hereinafter, a first embodiment of the fuel cell of the present invention will be described in detail with reference to the drawings. FIG. 1 is a system diagram of a fuel cell according to the present invention. Reference numeral 1 denotes a battery cell, in which an electrolytic solution and an electrode are provided, and by supplying hydrogen and air, hydrogen and oxygen in the air react to generate electricity. Since the battery cell of a fuel cell is common, detailed description is abbreviate | omitted.
[0010]
Reference numeral 2 denotes a fuel intake port for introducing fuel (hydrogen) sent from a fuel reformer (not shown) such as a hydrogen cylinder (not shown) or methanol, and 3 denotes an air intake port for introducing air. Reference numeral 4 denotes an exhaust port from which oxygen-depleted air and steam are discharged.
[0011]
Reference numeral 5 denotes a rotary moisture / heat exchanger, for example, an aluminum foil is formed in a honeycomb shape, and a moisture adsorbent such as silica gel is supported on the surface of the aluminum foil. Is something.
[0012]
The rotary moisture / heat exchanger 5 is rotationally driven by a motor (not shown) in the direction of the arrow in FIG. The rotary moisture / heat exchanger 5 is divided into an endothermic zone 6 and a heat radiating zone 7. In the heat absorption zone 6, latent heat and sensible heat are collected and taken away from the air system exhaust passing through this portion, and in the heat dissipation zone 7, latent heat and sensible heat are given to the air passing through this portion.
[0013]
Since the process of exchanging latent heat and sensible heat is known in many applications classified as the above F-term, description thereof is omitted here.
[0014]
A heater 8 is provided in a passage into the heat dissipation zone 7 and heats air sent to the heat dissipation zone. A drain pan 9 is provided below the endothermic zone 6 and receives water condensed in the endothermic zone 6. A humidity sensor 10 measures the humidity of the air before entering the air intake 3. Reference numeral 12 denotes a fuel system exhaust port.
[0015]
FIG. 2 is a flowchart showing the operating state of the fuel cell of the present invention. This operation can be easily realized using a commercially available sequencer or microcomputer. First, when the operation of the battery cell 1 is started, in step 1, the rotary moisture / heat exchanger 5 is rotated at a low speed and the heater 8 is energized.
[0016]
Next, in step 2, it is determined whether or not a predetermined time T has elapsed from the start of operation of the battery cell 1. If the predetermined time T has not elapsed, the process returns to step 1 to maintain the low speed operation of the rotary moisture / heat exchanger 5 and the energization of the heater 8.
[0017]
As a result, the outside air heated by the heater 8 passes through the heat dissipation zone 7 and releases the moisture adsorbed by the moisture adsorbent. Accordingly, the outside air is humidified and becomes humid air and enters the air intake 3 of the battery cell 1. In this manner, the humid air is supplied to the battery cell 1 for a predetermined time T, and moisture is supplied when the battery cell 1 is started up. Here, the predetermined time T is set so as to be a time until the battery cell 1 is fully functional.
[0018]
When a predetermined time T has elapsed from the start of the operation of the battery cell 1, the process proceeds to step 3, where the rotary moisture / heat exchanger 5 is rotated at a high speed and energization to the heater 8 is stopped. At this time, that is, after the predetermined time T has elapsed, the battery cell 1 is fully functioning, and high-temperature air and steam with reduced oxygen are discharged from the exhaust port 4 of the battery cell 1.
[0019]
While the high-temperature air and steam pass through the heat absorption zone 6 of the rotary moisture / heat exchanger 5, heat and moisture are given to the rotary moisture / heat exchanger 5. The rotary moisture / heat exchanger 5 rotates at a high speed and moves to the heat dissipation zone 7 in a short time. Then, heat and steam are given to the outside air in the heat radiation zone 7, and the outside air that has become hot and humid is supplied to the air intake 3. Power supply efficiency of the battery cell 1 is increased by supplying high temperature and high humidity outside air to the battery cell 1.
[0020]
Next, the routine proceeds to step 4 where it is checked whether or not the output w of the humidity sensor 10 is greater than a predetermined value W. That is, if the humidity of the air entering the air intake port 3 is too high, the power generation efficiency of the battery cell 1 is reduced, and therefore the humidity of the air needs to be a predetermined value W or less.
[0021]
That is, when the electric load of the battery cell 1 is large and the amount of power generation is large, the amount of supply air increases, the humidity of the air leaving the heat dissipation zone 7 decreases, and conversely, when the amount of power generation is small, the amount of supply air is small. The humidity of the air leaving the heat dissipation zone 7 becomes high.
[0022]
If the output w of the humidity sensor 10 is greater than or equal to the predetermined value, the process proceeds to step 5 where the rotation of the rotary moisture / heat exchanger 5 is decelerated and the recovery of water vapor from the exhaust of the battery cell 1 is reduced. On the other hand, when the output w of the humidity sensor 10 is equal to or less than the predetermined value, the process proceeds to step 6 where the rotation of the rotary moisture / heat exchanger 5 is increased and the recovery of water vapor from the exhaust of the battery cell 1 is increased. Thus, moisture and heat can be supplied according to the operating status of the battery cell 1.
[0023]
After adjusting the rotation of the rotary moisture / heat exchanger 5 in step 5 or step 6, the process proceeds to step 7 to determine whether or not to end the operation of the battery cell 1. If the operation is not ended, the process returns to step 4. When it ends, it proceeds to the end operation.
[0024]
The air supplied to the battery cell 1 by the above operation is sufficiently humidified from the start, and the rotary moisture / heat exchanger 5 is used for exchanging moisture and heat. However, since the exchange efficiency of moisture and heat is high, even a small rotary moisture / heat exchanger 5 can sufficiently exchange moisture and heat.
[0025]
In the first embodiment described above, an example in which moisture and heat exchange is performed between air and air system exhaust is shown. However, as in Example 2 shown in FIG. A rotary moisture / heat exchanger 5 ′ that performs moisture / heat exchange may be provided. Here, 6 ′ is an endothermic zone and 7 ′ is a heat radiating zone, which are substantially the same as the heat absorbing zone 6 and the heat radiating zone 7 of the first embodiment. Reference numeral 8 'denotes a heater for heating the hydrogen of the fuel.
[0026]
Reference numeral 9 'denotes a drain pan which is the same as the drain pan 9 of the first embodiment. The humidity sensor 10' is substantially the same as the humidity sensor 10 of the first embodiment and the pump 11 'is substantially the same as the pump 11 of the first embodiment. It is. The operation of the second embodiment is the same as that of the first embodiment, and a description thereof will be omitted.
[0027]
In the second embodiment, hydrogen as a fuel is sufficiently humidified from the start, and the efficiency of the battery cell 1 is improved. In addition, since the rotary moisture / heat exchanger 5 'is used for exchanging moisture and heat, the humidity and heat medium itself moves, and the humidity and heat exchange efficiency is high, so a small rotary moisture / heat exchanger is available. Even 5 ', sufficient moisture and heat exchange can be performed.
[0028]
In the first embodiment described above, moisture / heat exchange is performed between air and air system exhaust, and in the second embodiment, an example is illustrated in which moisture / heat exchange is performed between fuel and fuel system exhaust. As shown in the third embodiment, rotary moisture / heat exchangers 5 and 5 ′ for performing moisture / heat exchange between air and air system exhaust and hydrogen as fuel and fuel system exhaust may be provided.
[0029]
In each of the above embodiments, as the means for slowing the rotation of the rotary moisture / heat exchangers 5 and 5 ', the rotational speed is simply increased as the means for simply decreasing the rotational speed and increasing the rotation speed. By rotating the humidity / heat exchangers 5 and 5 ′ intermittently and adjusting the length of the stop time, the same effect as when the rotational speed is increased or decreased can be obtained.
[0030]
Even in the above embodiments, when the moisture supply at the time of starting is insufficient, the pumps 11 and 11 ′ for pumping the water received in the drain pans 9 and 9 ′ are provided to rotate the water in the drain pans 9 and 9 ′. Humidity at the time of start-up when the pumps 11 and 11 'are operated between the step 1 and the step 2 by dropping from the heat radiation zones 7 and 7' of the moisture / heat exchangers 5 and 5 '. The amount of supply can be increased.
[0031]
【The invention's effect】
Since the fuel cell of the present invention is configured as described above, it can be remarkably miniaturized as compared with the case where moisture in the exhaust gas is supplied to the supply air using a moisture permeable membrane, and water is vaporized by heat and supplied. Energy consumption can be remarkably reduced as compared with the case of humidifying air.
[0032]
That is, moisture and heat are moved from the exhaust to the supply air while moving the moisture and heat medium, so that even a small device can sufficiently exchange moisture and heat. In addition, after a predetermined time has elapsed from the start of operation, the humidity and heat of the exhaust gas are used as they are for humidification and heating of the supply air, so that energy consumption is small.
[0033]
Furthermore, since the fuel cell of the present invention uses the water generated when the fuel cell was operated before the start of operation, it is not necessary to supply water from the outside at the time of start-up, and maintenance is easy.
[0034]
In addition, the supply of moisture can be controlled according to the operating conditions such as when the battery cell is started or the load state, and the power generation efficiency of the battery cell can be optimized by setting the optimal humidification amount.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing Example 1 of a fuel cell of the present invention.
FIG. 2 is a flowchart showing the operation of the fuel cell of the present invention.
FIG. 3 is an explanatory view showing Example 2 of the fuel cell of the present invention.
FIG. 4 is an explanatory view showing Example 3 of the fuel cell of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Battery cell 2 Hydrogen intake port 3 Air intake port 4 Air system exhaust port 5, 5 'Rotary-type moisture and heat exchanger 6, 6' Endothermic zone 7, 7 'Radiation zone 8, 8' Heater 9, 9 'Drain pan 10 10 '' humidity sensor 11, 11 'pump 12 fuel system exhaust port

Claims (6)

The battery cell has a rotary moisture / heat exchanger that exchanges latent heat together with sensible heat between the battery cell and an air intake pipe to the battery cell and an air exhaust pipe from the battery cell. The air is sent to the air intake pipe through the heat release zone of the moisture / heat exchanger and the air exhaust is discharged to the atmosphere through the heat absorption zone of the rotary moisture / heat exchanger. A heater for heating before passing through the heat dissipation zone of the moisture / heat exchanger, a drain pan for receiving water condensed in the heat absorption zone, and a pump for sending the water accumulated in the drain pan to the heat dissipation zone, to the heater at the start of the operation only operation, the said heater to be lower than during normal operation the rotation of the rotary moisture-heat exchanger supplies the water to the heat radiation zone by operating the pump Fuel cell so as to control the operation of the pump and the rotary moisture-heat exchanger. A battery cell, and a rotary moisture / heat exchanger for exchanging latent heat together with sensible heat between a fuel intake line to the battery cell and a fuel system exhaust line from the battery cell. Through the heat release zone of the moisture / heat exchanger and the fuel exhaust to the atmosphere through the heat absorption zone of the rotary moisture / heat exchanger, and the fuel rotates. A heater for heating before passing through the heat dissipation zone of the moisture / heat exchanger, a drain pan for receiving water condensed in the heat absorption zone, and a pump for sending the water accumulated in the drain pan to the heat dissipation zone, to the heater at the start of the operation only operation, the said heater to be lower than during normal operation the rotation of the rotary moisture-heat exchanger supplies the water to the heat radiation zone by operating the pump Fuel cell so as to control the operation of the pump and the rotary moisture-heat exchanger. A battery cell, a first rotary moisture / heat exchanger for exchanging latent heat together with sensible heat between an air intake line to the battery cell and an air exhaust line from the battery cell; to the battery cell Having a second rotary moisture / heat exchanger for exchanging latent heat with sensible heat between the fuel intake pipeline of the battery and the fuel system exhaust pipeline from the battery cell, and the atmosphere is used for the first rotary moisture / heat. through heat radiation zone of exchanger air system exhaust through the heat absorbing zone of the first rotary moisture-heat exchanger so as to release into the atmosphere as well as to send the air intake conduit, the first rotary moisture A first drain pan that receives water condensed in the heat absorption zone of the heat exchanger, a first pump that sends the water accumulated in the first drain pan to the heat dissipation zone of the first rotary humidity / heat exchanger, and the fuel passing the heat radiating zone of the second rotary moisture-heat exchanger The fuel system exhaust through the endothermic zone of the second rotary moisture-heat exchanger so as to release into the atmosphere as well as to send the fuel intake conduit Te, the endothermic zone of the second rotary moisture-heat exchanger A second drain pan that receives the water condensed in the second drain pan, a second pump that sends the water accumulated in the second drain pan to the heat dissipation zone of the second rotary humidity / heat exchanger, and the atmosphere for the first rotary moisture / heat a first heater for heating prior to passing the heat radiating zone of exchanger, a second heater for heating prior to passing the fuel in heat radiation zone of the second rotary moisture-heat exchanger is provided, the operation at the start of the battery cell Only the first and second heaters, the first and second pumps are operated, and the first and second rotary moisture / heat exchangers are rotated slower than in normal operation. And the first and second times Fuel cell so as to control the operation of the equation moisture-heat exchanger. 4. The fuel cell according to claim 1, wherein the heater is operated only at the start of battery cell operation, and the rotation of the rotary moisture / heat exchanger is made slower than that during normal operation. The fuel cell according to claim 4, wherein the rotational speed is lowered as means for slowing the rotation of the rotary moisture / heat exchanger from that during normal operation. 5. The fuel cell according to claim 4 , wherein the rotation of the rotary moisture / heat exchanger is intermittent rotation as means for slowing the rotation of the rotary moisture / heat exchanger from that during normal operation.

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